I noticed the rates ($110 for std view/$164 for savannah view) too on Expedia. Since I like to have the UPH, I was going to book on Expedia, but then found out I had to pay the full amount ($3400) upon reservation.
I then called WDW, they offered me the same package (2 rooms, 5 nights savanah view) for the same price (actually the cancellation waiver was cheaper at WDW). I pay a $200/room down payment within 30 days and the rest 45 days before arrival. I think they also offered room only for the same prices ($110 for std view/$164 for savannah view). In that case, the down payment would only be the first night.
PS, I did the math, they charge you regular advance purchase rates (posted on the Disney website) for the UPH.